UNIX performance: RHEL5 server is slow

Hi,

The developers here are acusing that the RHEL5 servers are slow. They run weblogic tests on these servers. They have shown from their logs that weblogic server on RHEL5 takes a long time (3 minutes) to start in comparison to that of a SuSE 10 server (1 minute).

This is not a problem related to only one RHEL5 server. We have complains regarding all the RHEL5 servers here (both x86_64 and IA64).

From the output of top, I can see that a lot of processes are sleeping. At any time, I would see only one or 2 processes in the run state. Is this a normal thing even on a multiprocessor server?

I went through the sar (system activity report) on one of the server during the start of weblogic. Following are my observations: a. The RAM is almost completely used; however there is no swap usage. b. A lot of processes being created. c. A lot of context switches happening. d. Seems like the process that is running; is hopping from one processor to another, and I see about 15% of each processor's time is spent waiting on I/O during that time. e. I also see some spike in NFS client activity during this time.